Gas lift apparatus



De@ 31, 1940. A. w. STEENBERGH 2,226,537

GAS LIFT APPARATUS lnvenlor: Alcxander VWhemusSeenberqh D- 31, l940- l fA. w. sTr-:r-:NBERGH 2,226,537

' GAs LIFT APPARATUS l Filed March 8, 1940vv 2 sheets-sheet 2 gi W 5f? sVE x y l mvlmk F lg. Il

lnvenljor: Alexander Wilhelmus Srecnber'qh` Dg his Affomell'wg/ PatentedDec. 31, 1940 l UNITED STATES PATENT oI-'Ftcs GAS LIFT APPARATUS ofDelaware Application March 8, 1940, rSerial No. 322,888- In theNetherlands March 14, 1939 Claims. f 103-231) The present inventionrelates to gas lift pumps having a chamber for the accumulation of welll sure gas continuously to an accumulation cham' ber which is providedwith a level-responsive gas discharge device to vent the pressure gas tothe space between .the well casing and the gas supply string. However,the disadvantage of such anarrangement is that a considerable amount ofpressure gas is wasted and, consequently, in some wells, due to the costof vthis wasted pressure gas, the production of oil therefrom isuneconomical.

It is, therefore, an object of this invention to provide a pumpingarrangement having an accumulation chamber which is provided with alevel-responsive discharge device and a gas supply device automaticallycontrolling the area of passage of pressure gas to the accumulationchamber, whereby the gas supply to the chamber is restricted during theperiod of liquid accumulation, and the amount of pressure gas wasted isconsiderably diminished.

Other objects and advantages will be apparent from the followingdescription taken in reference to the drawings, wherein:

Figure I is a schematic vertical sectional view of a preferredembodiment of the present apparatus. Figure 1I is a schematic verticalsectional view of an adaptation of the present invention to deep wellpumping.

Briefly, the present invention comprises a liquid accumulation chamber,an eduction tube depending thereintdga level-responsive discharge device40 in said chamber, and a pressure-responsive device adapted to. supplypressure gas to said chamber at a restricted rate during the period ofliquid accumulation in said chamber.

VReferring to Figure I of the drawings, within a well casing I providedwith a perforated lower portion 2, such as a liner screen, depends atubing string forming a gas-supply column 3, which has fastened to itslower end a liquid accumulation chamber 4. The upper end of the gassupply string 3 is provided with a conduit 6, leading to a source ofpressure gas, and the upper end of thecasing i is provided with aconduit 6 for venting the space between the casing I and gas supplystring 3 and/or other usual or desired purposes. Within the gas supplystring 3 and depending into the accumulation chamber 4 is a tubingstring or eduction tube 1.

The lower ends of the eduction tube 1 and the accumulation chamber 4 areprovided with upwardly-opening one-way valves, such as ball valves 8 andlwhich are provided with cages I0 and Il, respectively. e

An opening l5 communicates between the accumulation chamber 4 and a lowpressurezone, such as the annular space I6 between the casing 10 landthe gas supply string 3. For the purpose of opening and closing saidopeningli responsive tothe liquid level within the accumulation chamber4, a valve l1 registering with said opening I5 ls carried by anelongated valve stem 18. The 15 stem I3 ts slidably within suitableguides, such as guide members i9 and 20 which are fastened within theaccumulation chamber 4. Near its lower end and near its upper end thevalve stem I8 is ntted with stop members 25 and 26, respec- 20 tively.Freely movable in al vertical. direction about the valve stem Il andbetween the stop members 26 'and 2t thereon, is a float 21 constructedso as tohave a specific gravity less than oil well liquids. The float21, for example, may 25 be of material such -as wood `(as shown) or maybie oi a-hollow metal or other suitable construc-- Communication betweenthe gas supply string 3 andthe accumulation chamber 4 is provided 30 bymeans of'an 'opening 3l containing an upwardly-opening valve member 3lnormally held in open position by resilient means, such as helicalspring 32, carried by spring support 33.I In a preferred arrangement thevalve member 3l is 35 constructed with a small bore 34 therethrough sothat pressure gas can flowat all times although sometimes at arestricted rate into the accumulation chamber 4 irrespective of theposition of the valve member 3l. It is apparent that an equallyv 40 vefiicacious arrangement is obtained if the gas passage formed by. thesmall bore 34 is provided outside the valve 3| at some other suitableplace in the partition between the gas'supply string 3 and theaccumulation chamber or any arrange- "45 ment providing vtor continuousleakage from the gas supply string to the accumulation chamber.

To lighten .iurther the column of well liquids rising in the eductiontube 1, a port `411 may be provided i! desired for' communicationbetween 50 the supply string 3 and the eduction tube 1 at a pointpreferably near the accumulation chamber `4. The port 4I allows pressuregas to bubble .up through the v lell liquids in the Veduction tube 1which decreases the 'density of said liquids and 55' ystarting with theaccumulation chamber 4 empty,

the float 21 rests on the lower stop member 25 of the valve stem I8causing the valve I1 attached thereto to expose the opening I5. As thepres'- sure in the chamber 4 is thus allowed to escape into the annularspace I6, the resultant difference in pressure between the accumulationchamber 4 and the gas supply string 3 causes the valve 3I to close theopening 30 against the action of the spring 32 due to the greaterpressure on the upper face of the downwardly closing valve 3l. Hence, byadjusting the tension of the spring 32 and properly selecting the areasof the valve exposed to the pressures in the gas supply string and inthe chamber, the valve 3I can be caused to close when the pressure inthe gas supply string 3 exceeds the pressure in the chamber 4 by anypredetermined value.

However, a restricted flow of pressure gas is permitted to flow into thechamber 4 through the small bore 34 in the valve 3l. Due to the lowpressure in the chamber 4 the ball valve 9 lifts to permit well liquidsto ow from the formation through the perforated portion 2 of the casingI and valve 9 to the accumulation chamber 4. As the liquid level in thechamber 4 rises, the iioat 21-rises until it contacts the upper stopmember 26 of the valve stem I3, whereby further rise of liquid levelcauses the float 21 to close the opening I5 with the valve I1. Then, asthe gas owing slowly into the chamber 4 through the small bore 34 isprevented from escaping, the pressure within the chamber 4 builds upuntil a predetermined value is reached at which value the spring 32 isstrong enough to overcome the decreased difference in pressures betweenthe 40 supply string 3 and the chamber 4 andV forces the valve 3i intoan open position. The full pressure from the gas supply string 3 is thenimpressed on the liquid in the chamber 4 through the opening 3|! andcauses the ball valve 9 to 45 close and the ball valve 8 to open,whereby the liquid in the chamber 4 `is forced upwards in the eductiontube 1 and on to the well head wherev 50 until it rests on the lowerstop member ,25 and thus moves the valve stem IB and valve I1 downwardand exposes the opening l5, whereby the gas is discharged from thechamber 4 and the pressure therein quickly lowered so that the valve 3lis caused to close the opening 30 and another period of liquidaccumulation begins. x

When it is preferable to lift the well liquids in several stages, suchas in a deep well, several chambers 4 may be arranged one above theother as shown in Figure 1I, wherein like numerals indicate partssimilar to those of the one-stage embodiment shown in Figure I. In thismultistage embodiment A denotes the uppermost stage, B the intermediatestage, of which there may be several, and C the lowermost stage. Anextension 50 of the gas supply string 3 passes down through stages A andB and is provided with side conduits 5I opening above the valves 3lin'each of stages 70 A, B, and C. The modified eduction tubes 52 in eachof stages B and C extend from the lower portion of each chamber 4 to thechamber 4 of the stage above it and are provided with upwardly-openingball valves 8 at their lower ends and, although this may not be strictlynecessary,

said chamber and a space of low pressure, oatwith upwardly-opening ballvalves 53 at their upper ends.

By this arrangement well liquids enter the lowermost stage C as in thesingle stage embodiment of Figure I and are lifted through the modiiied5 eduction tube 52 and empty into the stage B above it and so on untilthe Well liquids are raised to the well head and discharged.

By suitably adjusting the springs 32 of the valves 3l and the oats ofthe valves I1, the l0 operation of each stage may be made responsive toa desired pressure difference, if necessary.

It will be understood that various changes and modifications can be madewithout departing from the spirit of the present invention. Forinstance, it will be apparent that the oat operating the valve I1 fordischarging the gas supply to chamber 4 during the period of liquidaccumulation may be replaced by a. diaphragm.

This diaphragm should preferably be located in the lower portion ofchamber 4 and should be exposed, for example, on one side to thepressure of' the liquid rising and falling in said chamber and on theother side to the pressure of the gas above said liquid.

The diaphragm may be connected to valve stem I8 by means of a suitablelever mechanism.

I claim as myinvention:

l. In a gas lift system, a liquid collectingchamber, adapted to beplaced in a well, non-return liquid inlet and gas outlet valves betweensaidl chamber and the well, level responsive means within the chamber toclose the gas outlet valve, an eduction tube in communication with saidchamber, a non-return inlet valve in the lower portion of said tube, agas supply tube, reduced oriiice means in continuous communicationbetween said tube and said chamber, and loaded valve means adapted toopen between said tube and said chamber when the pressure diierencetherebetween falls below a predetermined value.

2. In a gas lift system, the combination of a tubular string extendinginto a well, a liquid accumulating chamber attached to the lower portionof said tubular string, a non-return inlet valve opening to said chamberfrom the well, an eduction tube depending into said chamber, anon-return inlet valve in the lower portion of said tube, an openingcommunicating between operated means responsive to the rise and fall ofliquid level in said chamber to close and open said opening, and meansfor delivering pressure gas through said tubular string to said chamber,said means comprising a valve, resilient means holding said valve inopen position, said valve being adapted to close against the action ofsaid resilient means when the pressure in said tubular string exceedsthe pressure in said chamber by a predetermined amount, and a restrictedpassage between said tubular string and said chamber, adapted to allowcontinuous ilow of a small amount of pressure iiuid into said chamber.

3. In a gas lift system, the combination of a tubular string extendinginto a well, a liquid accumulating chamber attached to the lower portionof said tubular string,anonreturn inlet valve opening to said chamberfrom the well, an eduction tube depending into said chamber, a nonreturninlet valve in the lower portion of said 70 tube, an openingcommunicating between said chamber and a space of low pressure,float-operated means responsive to the rise and tall lof said openingand means for delivering pressure holding said valvefin open position,said valve means being adapted to close against the action of saidresilient means when the pressure in said tubular string exceeds thepressure in said chamber by a predetermined amount, and a small bore insaid valve forming a restricted passage between saidxtubular string andsaid chamber adapted to allow continuous iiow of a small amount ofpressure fluid into said chamber.

4. In a gas lift system, the combination of a tubular string extendinginto a wellya liquid accumulating chamber attached to the lower portionofsaid tubular string, a non-return inlet valve opening to said chamberfrom the well, an eduction tube' depending into said chamber, anon-return inlet valve in the lower portion of said tube, an openingcommunicating between said chamber and a space of low pressure,oatoperated means responsive to the rise and fall of liquid level insaid chamber to closeand open said opening, passage means communicatingbetween said tubular string and said eduction tube at a point abovesaidchamber, and means for delivering pressure gas through said tubularstring to said chamber, said means comprising a valve,

resilient means holding said valve in open position, said valve beingadapted to close against the action of said resilient means when thepressure in said tubular string exceeds the pressure in saidV chamber byapredetermined amount, and a restricted passage between said tubular'-ystring and said-chamber adapted to allow continuous ilow ,of a smallamount of pressure uid into said chamber.

5. In a gas lift system, the combination of a tubular string extendinginto a well, a'plurality of liquid accumulating chambers verticallyspaced in said Well, a non-return inlet valve opening to the lowermostof said vchamber from the well eduction tubes depending into each ofsaid chambers, the eduction tube depending into the uppermost chamberextending to the surface of the well, each of the other eduction tubesextending from one chamber and opening into the chamber above said onechamber, one-way inlet valves in the lower portion of said tubes, andmeans associated with each of said chambers comprising an openingcommunicating between the chamber and a space of low pressure,float-operated means responsive to the rise and fall of liquid level inthe chamber to close and open said opening and means for deliveringpressure gas through said tubular string to the chamber said meanscomprising a valve, resilient means holding said valve in open position,said valve being adapted to close against the action of said resilient-means when the pressure in said tubular string exceeds the pressure inthe chamber by a predetermined amount, and a restricted passage betweensaid tubular string and said chamber adapted to allow Acontinuous now ofa small amount of pressure iiuid into the chamber.

ALEXANDER WILHELMUS S'I'EENBERGH.

